Why do some people believe that there are not 7 continents?

Answer 1

Probably because North & South America are linked (and should theoretically be ONE continent) - and Europe, Africa, and Asia are all one land mass (and again should be treated as one continent).

Answer 2

Some people may argue that there are not 7 continents because the definition of a continent is not universally agreed upon. In some classifications, Europe and Asia are considered one continent (Eurasia), while in others they are considered separate continents. Additionally, some argue that Australia is not a continent but rather a large island due to its size and proximity to Asia.